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Reaction mass of methyl chloroacetate and chloroacetic acid:

1.- Monochloroacetic acid: Experimental results: Two studies with Scenedesmus subspicatus were independently performed at two different laboratories. The obtained results for biomass and growth were within the same range, i.e. 25-28 μg/l for biomass and 30-70 μg/l for growth (48-72 hour EC50-values). In the 72 -hour study, the NOEC is 0.0058 mg/l and in the 48 -hour study, the NOEC is 0.007 mg/l (based on biomass) and 0.014 mg/l (based on growth rate). These results, which are below 1 mg/l, support the classification of the substance monochloroacetic acid as Hazardous for the Aquatic Environment, Acute Category 1. The substance is classified in the harmonised list of classification and labelling (CLP Regulation) as Hazardous for the Aquatic Environment, Acute Category 1.

2.- Methyl chloroacetate: Experimental results are available from studies conducted in fish with the substance methyl chloroacetate. However, no analytical monitoring was conducted during the studies. Therefore, there is no evidence that the concentration of the substance was maintained during the tests. ECOSAR calculations were conducted for both methyl chloroacetate and the analogue ethyl chloroacetate. The outcome of this calculations is that the LC50 values for fish for both substances are below 1 mg/l. These results support the classification for methyl chloroacetate as Hazardous for the Aquatic Environment, Acute Category 1.

The analogue ethyl chloroacetate which shares the same functional group with methyl chloroacetate, also has comparable values for the relevant molecular properties for the aquatic toxicity endpoint. These properties are:

- a low log Pow value which is 0.94 -1.12 for ethyl chloroacetate and 0.63 for methyl chloroacetate,

- a high water solubility which is 20 g/l at approximately 20 ºC for ethyl chloroacetate and 51.6 g/l for methyl chloroacetate and

- similar molecular weights which are 122.55 for ethyl chloroacetate and 108.52 for methyl chloroacetate.

The analogue ethyl chloroacetate is included in the list of harmonised classifications and labellings and it is classified as Hazardous for the Aquatic Environment, Acute Category 1.


Based on the aquatic toxicity data for the substances mentioned above and their concentrations, the following classification is proposed following the classification criteria for mixtures included in the CLP Regulation:

Hazardous for the Aquatic Environment, Acute Category 1 (since the reaction mass contains more than 25% of substances classified under this category).